Great Divergence Exists in Chinese Provincial Trade-Related CO2 Emission Accounts.

Accurate accounting of greenhouse gas (GHG) emissions considering interregional trade are important for developing regional-specific strategies for climate mitigation in countries like China where vast heterogeneity exists among regions. Trade-related provincial CO2 emission accounts have been reported and analyzed for China using three independently developed multiregional input-output (MRIO) models which have been widely used. Here we show that significant divergence exists in both consumption-based and income-based CO2 emission accounts for Chinese provinces in 2012 using different MRIO models. For example, the difference of CO2 emissions for Shandong Province calculated from two MRIO models can reach 208Mt, more than the terrestrial emissions of Argentina, United Arab Emirates, or The Netherlands. Reducing such divergence, however, requires only the agreement among various MRIO models on a small number of critical data elements. Our results demonstrate the need of careful interpretation of previous studies on trade-related provincial GHG emission accounts in China, and prioritize future efforts to harmonize GHG emission accounting within China.